To fully appreciate the present invention, some explanation of the rapidly developing field of electronic music generation and some discussion of the conventional guitar may be in order.
Prior to the development of music synthesizers, electronics intervened in the production of music at the musical instrument in the form of transducers which were associated with vibration-generating and sound-generating parts of a conventional or even a modified music instrument to produce an electronic signal, generally of an analog type, representing the vibrations generated by, for example a vibrating string, a resonating air column, a resonating chamber or the like.
In a guitar, for example, an electronic transducer, which could be a piezoelectric pick-up or another type of microphone, could be mounted upon the soundboard, the fret-carrying arm or neck of the guitar, or elsewhere on the latter, and perhaps connected to an amplifier to provide an amplified output capable of reproducing the sound actually generated and detected by the pick-up.
Similar pick-ups could be provided on other electronic instruments including keyboard instruments.
When it was desired to superimpose upon the sound generated by the instrument and sensed by the pick-up various effects or so-called "expression", or to provide a rhythmic effect, electronic sound generators were provided to operate under some degree of player control or even independently of such control, to contribute their outputs to the electronic circuitry through which the signals from the instrument were processed, or to modulate the signals supplied to such circuitry from the pick-up.
In part because of the great limitations on the versatility of such systems, electronic music synthesizers were developed which substituted for the tone generation by a vibrating string or the like, electronic music generation by switches and similar elements. In such music synthesizers, therefore, the tone generation derives from an electronic source and the electronic signals were modified, provided with overtones, harmonics or other effects which were outputted also after amplification. Early generations of such synthesizers were of an analog type and a natural progression has been to the more recently developed digital synthesizers.
More recently, it has been found to be desirable to provide instrument controllers for such music synthesizers, i.e. controllers which are operated in the manner of musical instruments and which can control the synthesizer to generate electronic signals with greater versatility and freedom of operation because the controller can be manipulated in the same manner as the corresponding musical instruments.
Thus the aforementioned copending application describes a keyboard-type controller for a music synthesizer which has possibly the greatest versatility in the electronic music field at this time, being fully programmable but nevertheless operable by keyboard fingering identical to that of any piano keyboard. With the system of this earlier application additional forms of expression can be provided to the music generated which have no counterparts in earlier keyboard instruments.
To date, however, as far as I am aware, it has not been possible heretofore to provide a corresponding input or controller for such a high level music synthesizer which uses guitar characteristics. This is not to say that there have not been efforts to develop electronic musical instruments based upon a guitar or utilizing the strumming and fretwork or fingering of a guitar. Indeed, such instruments included those described in the following U.S. Pat. Nos.: 3,456,063; 3,553,336; 3,609,201; 3,609,203; 3,662,241; 3,742,114; 3,767,833; 3,781,451; 3,795,756; 3,805,086; 3,842,358; 3,902,395; 3,916,751; 3,940,693; 3,948,137; 3,999,458; 4,038,897; 4,045,731; 4,080,574; 4,150,253; 4,151,775; 4,177,705; 4,193,332; 4,195,544; 4,202,234; 4,203,338; 4,300,431; 4,306,480; 4,010,668; 4,357,852; 4,143,575; 4,372,187; 3,578,894; 4,336,734; 3,694,559; 4,052,923; 3,555,166; 3,673,304; 3,960,044; 3,927,593; 2,500,172; 4,321,852; and 4,263,520.
See also AES Preprint 1828 (G-3): "The Fiber Optic Guitar", George A. Bowley, Dynamic Systems Inc. McLean, Va. and AES Preprint 1394 (J-4): Hall Effect Pickup For Stringed Musical Instruments, Robert M. Iodice, M. S. Kennedy Corporation, Syracuse, NY.
From these patents it will be apparent that considerable effort has gone into the development of electronic guitar-based musical instruments and perhaps at this point a brief reprise as to the construction of an ordinary guitar may be in order.
A guitar is simply a string instrument having a neck or arm and soundboard, generally but not always associated with a resonating body, to which a set of strings in mutually spaced-apart relationship are fixed and tensioned. The neck is provided with longitudinally spaced, transversely extending frets which define the particular notes obtained when the effective lengths of the springs are changed by fingering, i.e. the pressing of each string against an appropriate fret as the string is strummed or plucked.
Depending upon the skill of the player, the strumming and the fingering will be more or less rapid.
The early efforts to convert such a guitar into an electronic musical instrument employed pitch-to-voltage converters for each of the guitar strings to translate the vibration of the string into a control voltage. Since a music synthesizer of conventional design could make use of a voltage-controlled oscillator, this control voltage could be used to operate the oscillator and hence as an input to the synthesizer.
This system is inherently slow since several cycles of the string vibration are required before the control voltage transducer responds, the control voltage is generated and the control voltage is effective at the variable frequency oscillator.
For the lowest pitch string, this can mean a delay of some 25 milliseconds, a delay which is completely unsatisfactory especially when a high resiliency response to a guitar controller is required.
In practice, the generation of inputs to voltage-controlled oscillators for such an instrument was accompanied by the creation of a buzzing sound which could be attributed to sloppy use of the fretboard.
Several solutions were proposed and have been tried. For example, it has been proposed to provide a guitar-like instrument which dispenses with the strings entirely. In this arrangement the neck of the guitar is provided with a series of capacitive switches, while other switching or circuit means were utilized to provide a representation of a strumming action. This system provided a truly fast response but it was not common that the feel of the instrument was considered to be too unguitar-like.
Apparently the natural relationship between the fingering of the strings of the fretboard and the strumming or plucking action could not be maintained in this system and the fingering at the fretboard frequently preceded the strumming which was supposed to be associated therewith to produce discordant sounds. Other problems include the lack of versatility and the lack of an ability to give true expression to the electronically generated sounds.